Refrigeration and space heating systems used in industry and for domestic use have relied on Freon gas-cycles. Research has shown that the release of Freon into the atmosphere deteriorates the ozone layer in the Earth's atmosphere. The ozone layer is a protective layer that shields the earth from ultraviolet rays. The resultant harmful effects from an increase in ultraviolet rays can cause serious problems such as higher incidences of skin cancer. As a result, magnetic heat pump technology has been developed as an alternative to the use of Freon gas-cycle to provide refrigeration and space heating. The magnetic heat pump has the potential of being more efficient than a compressor driven refrigerator by using less power for the same amount of cooling.
A magnetic heat pump consists of a rotor of magnetic material such as gadolinium, which slowly rotates through a magnetic field formed from magnets. The type of magnets used can depend on the degree of cooling desired. For greater cooling, a super conductor magnet may be used. For lesser cooling, a permanent magnet with a weaker magnetic field may be used. The rotor has an enclosure with flow passages to allow heat transfer fluid to move through the rotor. The control of fluid flow direction through the rotor is difficult because the fluid has to flow into, through the material, and out of the material in one direction as the material is moved in the opposite direction.
FIG. 1 illustrates a flow schematic of the fluid flow area in a magnetic heat pump 100 without flow directors. The magnetic heat pump 100 consists of a rotor 5 of magnetic material which slowly rotates through a magnetic field 102 which has been formed from a magnet. The rotor 5 has an enclosure with flow passages 12 to allow heat transfer fluid to move through the rotor 5. The magnetic material 5, such as the rare earth metal gadolinium, may be in small spheres, chunks, discs plates, or any shape that would allow fluid to flow through it. In FIG. 1, rotor 5 was constructed of flat parallel discs of working material with a very small space in between each disc pair. The curie point temperature of the magnetic material 5 is the same as the temperature of the fluid passing through it. FIG. 5a illustrates magnetic material 5 in the form of stacked disc plates with the space 12 in between the disc plates for allowing fluid flow. FIG. 1 shows the fluid flow in the space 12 between two of the disc plates 5.
In FIG. 1, as the magnetic material passes through the point 30 to point 40, the electrons in the material 5 align themselves in the same direction and heat up. As the magnetic material 5 moves out of the magnetic field 102 from 40 to 30, the material 5 cools. The rotor 5 moves in a housing with ports 10, 20, 30, and 40, for fluid to enter and exit the system as shown in FIG. 1. The rotor 5 rotates in the direction of arrow A. The ideal flow path for the fluid is input into the flow passage 12 at 10 and 30, and output at 20 and 40. In the passage area from 10 to 20, the fluid flow as represented by arrow B1 is cooled down by the magnetic material 5 which has been removed from the magnetic field 102. As the fluid flows through the passage from 30 to 40, the fluid is warmed by the magnetic material 5. As the fluid flows in the passage from 40 to 10, the fluid is pumped by pump 15 through a heat exchanger 17 which cools the fluid to complete the heat pump cycle. The basic problem is the splitting of the flow path. As cold fluid enters the passage at 10, some fluid passes along the passage to 40 as represented by arrow C2 and mixes with warm fluid coming from the magnetic field 102. As fluid enters the heat exchanger 27, some of the cold fluid bypasses the heat exchanger 27 to flow instead along arrow C1 to the magnetic field 102. This fluid is heated up without getting to cool at the heat exchanger 27. Thus, fluid flow along arrow C1 mixes with fluid entering at point 30. Likewise fluid flow along arrow C2 mixes with the fluid of arrow B2. The split flows which occur at points 10 and 30 that cause fluid mixing significantly decreases the efficiency of the heat pump.
Prior art solutions to redirect fluid flow through a moving wheel in a magnetic heat pump appear to have utilized seals in the wheels or housings and/or segmented wheels to accomplish the pumping of heat transfer fluid through the rotating working materials. For example U.S. Pat. No. 4,107,935 which is incorporated by reference shows such a system where a rotary magnetic refrigerator uses a wheel segmented into spaces through which heat transfer fluid flows radially in the segments, back and forth. This patent appears to require a complex design for a segmented wheel that could limit the practical usability of the device. Thus, the inventor is not aware of any method of adequately directing the fluid flow in heat pumps.